Variable blade drafting device



May 5, 1970 G- A. ALLKSQN VARIABLE BLADE DRAFTING DEVICE 4 Sheets-Sheet 1 Filed April 23, 1969 R m w w w ER/QLD H. QLL/SOA G. A. ALLISON VARIABLE BLADE DRAFTING DEVICE May 5, 1970 4 Sheets-Sheet 2 Filed April 25, 1969 M/VE N TOR GER/7L. U H. FILL/50A H T TOR/11E) May 5, 1970 G. A."ALL|SON VARIABLE BLADE DRAFTING DEVICE Filed April 2:5, 1969 4 Sheets-Sheet 5 //UVE/UTOR. GERALD IQ. fiLL/SOA) y 1970 5. A. ALLISON 3,509,632

VARIABLE BLADE DRAFTING DEVICE 45 M/VE/UTOA.

65/?HLD H. rQLL/SOA) :QTTORNEX nited States Patent 3,509,632 VARIABLE BLADE DRAFTING DEVICE Gerald A. Allison, 11 Ryerson Place, Pompton Plains, NJ. 07444 Filed Apr. 23, 1969, Ser. No. 818,574

Int. Cl. B431 13/14 U.S. Cl. 3375 15 Claims ABSTRACT OF THE DISCLOSURE A drafting device used for the creation of physical relationships to intangible points of reference (vanishing points) which points can be accurately projected as close to an illustration working area as five inches, as distant as infinity. The device consists of a straight edge ruler having a pair of variable blades adjustably attached to one end thereof and a pair of pivot pins associated with the variable blades to permit manipulation of the straight edge ruler to draw parallel lines which converge at intangible points as determined by the angular relationship setting of the pair of variable blades to the straight edge ruler. Various accessories are provided, such as an incline plane attachment to create intangible convergence points for perspective parallel lines of incline planes, variable blade extension attachments to increase the size of the illustration area and a bracket for are ruling instruments.

This invention pertains to a drafting device used for the .creation of vanishing points having a projection range of five inches from an illustration area to infinity to aid designers, engineers, artists, draftsmen, architectural renderers, etc. in the preparation of perspective illustrations.

One of the principal objects of the present invention is to provide a drafting device for the creation of vanishing points at unlimited locations, beyond five inches, for perspective illustrations.

Another object of the invention is to provide an intangible center point for circular, concentric arcs with unlimited radius lengths beyond five inches.

A further object of the invention is to provide an arc ruling attachment which is adjustable along the straight edge ruler of the device for ruling concentric arcs with unlimited radius lengths.

A still further object of the present invention is to provide for the creation of radial sectors which may intersect concentric arcs at 90.

Yet another object of the invention is to provide an incline plane attachment for perspective parallel lines of incline planes which properly relate to the convergence point of their counterpart, horizontal plane.

A further object of this invention is to provide for the orientation of the incline plane attachment on the main straight edge ruler i.e.: its ease of traverse on that ruler and its ability to remain in a fixed position thereon.

A still further object of the present invention is to provide calibrated sector grids on each of the variable blades of the device with indicia directly readable on the grid lines to enable the user to set the angle of the variable blades to obtain a desired distance between the illustration area and the vanishing point.

Yet another object of the instant invention is to provide reference radials in protractor form on the incline plane attachment for the analysis and notation of incline planes, and to provide percentage factors at intervals thereon for the coordination of incline plane blades settings with their counterpart horizontal plane blade setting.

A further object of the invention is to provide a variable straight edge ruler which can be fixed at any angular position in relation to the main straight edge ruler and which ice 'will constantly refer all ruled lines to an intangible convergence point.

Other objects and advantages will become more fully apparent to those schooled in the art from the following detailed description of the present invention when read in conjunction with the drawings in which:

FIGURE 1 is a top plan view of the variable blade drafting device of the present invention illustrating the variable blades set at to the ruling straight edge;

FIGURES 2, 3 and 4 are views similar to FIGURE 1 illustrating variations of blade angle settings:

FIGURE 5 is an enlarged top plan view of the calibrated sector grids of the variable blades as seen in FIGURES 1 through 4;

FIGURE 6 is an enlarged top plan view of an incline plane accessory for the present invention as attached to the ruling straight edge thereof;

FIGURE 7 is a cross sectional view taken along the line 77 of FIGURE 6 and looking in the direction of the arrows;

FIGURE 8 is a further enlarged fragmentary top plan view illustrating the reference radials of the incline plane accessory in protractor form;

FIGURE 9 is an enlarged top plan view of an accessory bracket for an arc ruling instrument adjustably attached to the ruling staright edge;

FIGURE 10 is a cross sectional view taken along the line 10-10 of FIGURE 9 looking in the direction of the arrows;

FIGURE 11 is a front elevational view of the bracket and are ruling instrument of FIGURES 9 and 10;

FIGURE 12 is an enlarged cross sectional view taken along the line 12--12 of FIGURE 1 looking in the direction of the arrows;

FIGURE 13 is an enlarged cross sectional view taken along the line 1313 of FIGURE 1 illustrating one of the pivot point bushings;

FIGURE 14 is a top plan view of a modified form of the present invention; and

FIGURE 15 is atop plan view of the modified form of FIGURE 14 incorporating a pair of accessory variable blade extensions and the accessory incline plane assembly.

Referring to the drawing in which like reference numerals designate like parts throughout the various views, the numeral 20 generally indicates the variable blade drafting device of the present invention which is comprised generally of a main straight edge ruler 22, a pair of variable blades 24 and 26 and a coupler 28 for adjustably coupling the ruling straight edge to the variable blades 24 and 26.

As best illustrated in FIGURES 1 through 4 and 12, the variable blades 24 and 26 are pivoted to the coupler 28 by means of a screw threaded pin 30, in an overlapping relationship and include arcuate sgements 32 and 34 respectively. Each arcuate segment 32 and 34 is provided with an arcuate slot 36 and 38 having an equal radius from the pivot pin 30 and a screw threaded pin 40 also on an equal radius passes through a hole 42 (FIGURE 12) in the coupler and the arcuate slots 36 and 38 in the segments 32 and 34 of the variable blades 24 and 26. Each of the screw threaded pins 30 and 40 is provided with a thumb nut 44 and 46. By loosening the thumb nuts 44 and 46, the variable blades 24 and 26 may be pivoted from their respective positions of 90 to the straight edge ruler 22 of FIGURE 1 to any position within the limits of the 90 arcuate slots 36 and 38. For examples, in FIGURE 2 each of the variable blades 24 and 26 has been pivoted through equal arcs of approximately 45 in FIGURE 3, each of the blades 24 and 26 has been pivoted through a diiferent number of degrees and in 3 FIGURE 4, blade 26 remains at 90 to the ruling straight edge 22 while the blade 24 has been pivoted through approximately 45 A pair of pivot points 48 and 50 is associated with the variable blades as illustrated in FIGURES 1 through 4. As illustrated in FIGURE 13, each pivot is comprised of a headed push pin 52 which is inserted into the drafting table or working surface and a bushing 54 preferably of nylon is circumposed about the pin portion 56 to engage the edge 58 of one of the variable blades.

A pair of calibrated sector grids 60 and 62 is imprinted on or fixed to the arcuate portions 32 and 34 of the variable blades. Each of the sector grids 60 and 62 includes a plurality of radial lines projecting outwardly from the pivot pin 30 and, referring to FIGURE 5, also includes two scales 64 and 66 directly readable on the radial lines. The axial spacing between the pivots 48 and 50 has a direct bearing on the distance to intangible points of convergence (vanishing points) projected by the drafting device of the present invention and, by way of example, the scale 64 indicates this distance with the pivots 48 and 50 on a axial spacing and the scale 66 on a 20 axial spacing.

In use, the thumb screws 44 and 46 are loosened and blades turned to a desired angle by aligning the ruling edge 68 of the straight edge ruler 22 with the desired radial lines on the calibrated sector grids 60 and 62. Referring to FIGURE 2, for example, the edge will be approximately aligned with the radial indicating a vanishing point on the 10 axis scale and a 30 vanishing point on the axis scale. It is to be noted that the full scale does not appear on FIGURE 5 for the 20 axis scale due to the limitation of size of the drawing, however, the distance to vanishing point for each radial is double that appearing on the 10 axis scale. Lines projected from the ruling edges 68 of the drafting device shown in full lines and the device shown in phantom in FIGURE 2 would, therefore, form a point of convergence from the illustration working area of the user when the pivots 48 and 50- are axially spaced apart 20" or 15" when the axial spacing is 10".

By manipulating the variable blade drafting device of the present invention relative to the pivot points 48 and 50 as illustrated in FIGURE 2, any desired number of radial lines can be drawn from the intangible point of convergence within an area dictated by the axial spacing of the pivots 48 and 50 and the size of the drafting device. It is also apparent that the calibrated sector grid can be reset to create new reference points in seconds and set permanently for constant accuracy.

It will also be apparent to those skilled in the art that by varying the scope-horizon ratio working areas may be achieved with their varying positions in relationship to the picture horizon thus creating illusions of high or low and distant or close-up view points. With reference to the calibrated sector grid of FIGURE 5, it can be seen that vanishing points can be accurately projected as close to an illustration working area as five inches, as distant as infinity.

Normally the ruling edge 68 is in alignment with the pins 30 and 40, however, adjustment means are provided to accommodate various ruling instruments, i.e. pencil and/0r brush. The adjustment means comprises a pair of diagonally disposed slots 70 and 72 and associated thumb nut assemblies 74 and 76.

Referring to FIGURES 6, 7 and 8, an incline plane accessory 78 is illustrated which is used to create intangible convergence points (vanishing points) for perspective parallel lines of incline planes which relate to the convergence or vanishing point of their counterpart, horizontal plane.

To provide for the orientation of the incline plane assembly on the main straight edge ruler, its ease of traverse on that ruler and its ability to remain in a fixed position thereon, a clamping means 80 is employed. The body portion 82 of the incline plane assembly is preferably circular in configuration in the plan view and pro vides a portion 83 transversely spanning the bottom surface 84 of the straight edge ruler 22. An arcuate segment 86 fixed to the top of the circular body portion 82 adjacent the edge 88 of the straight edge ruler provide a groove 90 for the reception of the edge 88. The clamping means 80 comprises a strip 92 providing an undercut shoulder 94 to be against the edge 68 of the straight edge ruler and a lip portion 96 to overlie the top surface 98 of the straight edge ruler 22. A pivot screw 100 and thumb nut 102 which are associated with the strip 92 is utilized to selectively clamp or unclamp the incline plane accessory to the straight edge ruler 22 in the manner illustrated in FIG- URE 7.

A variable incline plane ruler 104 provides a portion 106 extending diametrically across the underside of the circular body portion 82 and is adjustably held in place by the pivot screw and thumb nut 100 and 102. As best illustrated in FIGURE 6, the pivot screw is positioned centrally of the circular body portion 82. A reduced width portion 108 of the straight edge ruler 104 extends outwardly beyond the circular body portion '82.

Referring to FIGURE 6, an arcuate slot 110 extends approximatetly 180 around the circular body portion 82 adjacent its outer periphery and a screw and thumb nut assembly 112 traverses the slot and extends through the portion 106 of the straight edge ruler 104 in a manner to selectively clamp or unclamp the ruler 104 in any desired position.

Therefore, it can be seen, that by loosening the thumb nut 102, the entire incline plane assembly can be slid longitudinally of the main straight edge ruler 22 and by also loosening the thumb nut 112, the incline plane straight edge ruler can be pivoted about the pivot screw 100. When both thumb nuts 100 and 112 are tightened, the incline plane assembly will be clamped to the main straight edge ruler 22 in any selected position and the incline plane straight edge ruler will be clamped in any selected position relative to the circular body portion 82.

Referring to FIGURES 6 and 8, the 180 portion of the circular body 82, provided with the arcuate slot 110, includes reference radials 114 in protractor form for the analysis and noation of incline planes. FIGURE 8 is an enlarged illustration of the protractor portion 116 and includes indicia 118 indicating 5 intervals and compensating percentage factors 120 for each 5 interval for the coordination of incline plane settings of the variable blades with their counterpart, horizontal plane variable blade setting.

As illustrated in FIGURE 6, the variable straight edge ruler 108 is pivotal through 360. A hole 122 is provided in the ruler portion 106 diametrically opposite the screw and thumb nut assembly 112 and on an equal radius thereto. By removing the thumb nut assembly 112 and pivoting the incline plane straight edge to the position illustrated in phantom in FIGURE 6, and inserting the screw of the thumb nut assembly through the hole 122 and the arcuate slot 110 it is seen that a rotation of a full 360 is provided for the ruler 108.

Therefore, the variable straight edge ruler 108 can be fixed at any angular position in relation to the main straight edge ruler 22 and will constantly refer all ruled lines to an intangible convergence point which is determined by a compensating percentage formula for coordinating the variable blade settings of the incline planes with their counterpart, horizontal plane variable blade setting.

Formula:

(HPS+AP) factor= (IPS+AP) IPS: (IPS-l-AP) --AP HPS=Horizontal plane setting.

IPS=Incline plane setting.

AP=Axis center to protractor center (at horizon). Factor=Compensation percentage factor at 5 intervals.

Factor selection is based upon the compensation percentage factor indicated on the 5 interval which most nearly aligns with the working position angle on the ruling edge of the incline plane straight edge ruler 108.

FIGURES 9, 1'0 and 11 illustrate a bracket 123 for are ruling instruments and generally consists of a transverse portion spanning the underside 84 of the straight edge ruler 22 and the adjustable attachment means is similar to the attachment means of the incline plane accessory, consisting of a groove 124, and a longitudinal bar and thumb nut assembly, 126 and 128 respectively. It is, therefore, apparent that the bracket 123 can be easily relocated to any position on the straight edge ruler and reset thereon in a fixed position.

As best illustrated in FIGURES and 11, the under-,

side of the bracket includes a pair of depending lugs 130 and 132, adjacent the ruling edge 68 of the straight edge ruler, to rotatably journal a roller unit 134. The rollers 136 and 138 traverse the drawing surface 140 to aid the pressure control of ruling instruments on the drawing surface.

At the forward end, outwardly of the edge 68 of the straight edge ruler, a vertically extending arm 142 is adapted to receive a ruling instrument 144 in a block 146 in the manner illustrated in FIGURES 10 and 11. A thumb nut assembly 148traverses a shank portion 1500f the drafting instrument144 to hold it firmly in place in the bore 152 of the block 146. An angular strengthening web 154 extends along the rear vertical face of the arm 142.

FIGURES 13, 14 and 15 illustrate a modified form of the variable blade drafting device of the present invention. The device as illustrated in FIGURE 14 is normally used for illustration areas of approximately. 14" x 20" with the pivot points 48 and 50 placed 10 apart. To achieve larger working areas, pivot points must be placed further apart. Each of the variable blades 156 and 158, FIGURE 14, is provided with a pair of holes 160 and 162 to provide for attachment of extension. members 164 and 166 to the blades 156 and 158 by attachment means 168. The axial spacing of the pivot points 48 and 50 may be substantially increased to increase the size of the illustration area. For instance, when the axial spacing between the pivots 48 and 50 is increased to 20", the illustration area is increased to approximately 20" x I claim:

1. A variable blade drafting device used to create intangible convergence points for perspective parallel lines on illustration areas comprising;

(1) a main straight edge ruler having,

(A) a longitudinal ruling edge,

(B) a second longitudinal edge substantially parallel to said longitudinal ruling edge, in opposed relation thereto;

(2) a coupler having a first end portion overlying one end portion of said main straight edge ruler and a second end portion projecting outwardly therefrom, said first end position including,

(A) adjustable attaching means including slot means and cooperating screw means therefor to securely hold said coupler to said main straight edge ruler;

(3) a pair of variable blades, each having one straight edge and including,

(A) pivot means attaching said variable blades to said coupler in an overlapping relationship at a point outwardly from and adjacent to said end portion of the main straight edge ruler in a manner to permit said pair to be pivotal from positions in which said straight edge of said pair extends outwardly from said longitudinal ruling edge at 90 in opposed relation to each other, to positions 0 wherein each of said straight edges of the variable blades extends outwardly from said longitudinal ruling edge and is parallel thereto,

(B) adjustment means to hold both of said variable blades to the outwardly extending end of said coupler in any angular position relative to said longitudinal ruling edge between said 0 and 2. A variable blade drafting device as set forth in claim 1 in which said adjustable attaching means comprises, a pair of elongated diagonally disposed slots in said coupler and a pair of screw and thumb nut assemblies associated with said slots, each of said screws extending upwardly through said main straight edge ruler and one of said slots to receive one of said thumb nuts to permit said longitudinal ruling edge of the main straight edge ruler to be adjusted relative to said pivot means.

3. A variable blade drafting device as set forth in claim 1 in which said pivot means comprises a screw extending upwardly through said overlapping portions of said coupler and variable blades and a thumb nut receivable on the upwardly extending end of said screw.

4. A variable blade drafting device as set forth in claim 3 in which said adjustment means comprises, an arcuate slot of substantially 90 in the pivot end of each of said variable blades, said arcuate slots being on an equal radius from said pivot means, having overlapping inner portions and extending arcuately outwardly in opposed directions, I

'5. A variable blade drafting device as set forth in claim 1 including a pair of pivot points set apart a predetermined distance and adapted to engage with said respective straight edges of said variable blades to establish intangible points of convergence ranging from approximately five inches from the illustration area to infinity, depending upon the angular setting of said variable blades, said intangible points of convergence being established by radials extending outwardly from said longitudinal ruling edge when said drafting device is manipulated relative to said pivot points.

6. A variable blade drafting device as set forth in claim 5 in which said pivot points comprise push pins inserted into the working surface.

7. A variable blade drafting device as set forth in claim 6 in which bearing sleeves are circumposed about said push pins at the point of engagement with the straight edges of said variable blades.

8. A variable blade drafting device as set forth in claim 1, including an incline plane attachement comprising a main body portion partially underlying said main straight edge ruler, adjustable attachment means for said main body portion to said main straight edge ruler providing traverse therealong and stability in any fixed position thereon, a variable incline plane ruler partially underlying said main body portion including pivot means permitting said variable incline plane ruler to be swingable through a full 360, and means for locking said variable incline plane ruler at any angle relative to said main straight edge ruler.

9. A variable blade drafting device as set forth in claim 8 including, reference radial lines at 5 intervals in pro tractor form on said main body portion, said radial lines eminating from said pivot means of said variable incline plane ruler; compensation percentage factors at each 5 interval for the coordination of the incline plane ruler and variable blade settings with their counterpart horizontal main straight edge variable blade setting by constantly referring all lines ruled along said variable incline plane ruler to an intangible convergence point determined by a setting formula.

10. A variable blade drafting device as set forth in claim 9 in which said formula is:

HPS=Horizontal plane setting,

IPS=Incline plane setting,

AP=Axis center to protractor center (at horizon), Factor=Compensation percentage factor at 5 intervals.

11. A variable blade drafting device as set forth in claim 8 in which said adjustable attachment means for said main body portion comprises a longitudinal groove therein for the reception of said second longitudinal edge of said main straight edge ruler, a longitudinal bar partially overlying said main straight edge ruler providing a shoulder extending partially downwardly along said longitudinal ruling edge, screw means extending upwardly through said incline plane straight edge ruler, main body portion and bar outwardly of an adjacent to said longitudinal ruling edge, and thumb nut receivable on said screw means to lock said incline plane attachment to said main straight edge ruler, said screw means forming said pivot means for said incline plane straight edge ruler.

12. A variable blade drafting device as set forth in claim '8 in which said means for locking said variable incline plane ruler at any angle relative to said main straight edge ruler comprises, a radial slot of substantially 180 in said main body portion on a radius from said pivot means of said variable incline plane ruler, removable screw means extending upwardly through a first hole in said variable incline plane ruler and said radial slot and a thumb nut receivable on said removable screw means; a second hold in said incline plane ruler, spaced 180 from said first hold on an equal radius therewith from said pivot means, to receive said removable screw means when said incline plane ruler is pivoted to align said second hole with said 180 arcuate slot.

13. A variable blade drafting device as set forth in claim 1 including an adjustable bracket attachment to said main straight edge ruler for the reception of an arc ruling instrument comprising, a base portion substantially underlying said main straight edge ruler, a slot for the reception of said longitudinal ruling edge, a longitudinal bar partially overlying said main straight edge ruler providing a shoulder extending partially downwardly along said second longitudinal ruling edge, screw means extending upwardly through said base portion and bar and a thumb nut receivable on said screw means to lock said bracket in any selected position; an upstanding arm portion including an outwardly extending block portion at its upper end providing a downwardly extending bore for the reception of the arc ruling instrument and thumb screw lock means to hold said are ruling instrument in a proper ruling attitude.

14. A variable blade drafting device as set forth in claim 13 including a rolling means on the surface of the illustration area comprising, a pair of lugs projecting downwardly from said base portion and a pair of rollers journaled therein.

15. A variable blade drafting device as set forth in claim 8 including an extension means for each of said variable blades comprising, calibrated sector grids having indicia thereon, and an elongated bar and attachment means holding said bar to said variable blade, said blade presenting a straight edge portion in alignment with said straight edge of said variable blade which extends outwardly substantially beyond said variable blade.

References Cited UNITED STATES PATENTS 430,647 6/ 1890 Hickock 33--77 1,064,878 6/1913 Young 33-77 FOREIGN PATENTS 941,014 6/1948 France.

OTHER REFERENCES Publication: Centrolinead, Mechanics Magazine, vol. 44, page 149, Feb. 21, 1846.

HARRY N. HAROIAN, Primary Examiner US. Cl. X.R. 33-77 

